As I recently started to use my laptop more often than my PC, I noted a small annoyance when scrolling down using the keys ↓ & ↑, it was just matter of time and bad luck until my cursor landed on a tag and this would cause to expand it, then after one (sometimes even two) ↓s later, the mouse will keep preventing the box from collapsing since it is still above the box, usually preventing me to read question titles located below them.
If you think of it, this happen very often since the mouse is usually located at the center of the page, (not to the top in fear of clicking/closing something important, same as bottom), then because of different sizes, it will eventually happen and will make you move the mouse away, after some more navigating it will happen again and again.
Proposed solution: prevent the box from expanding when using the arrow keys since the odds of someone really wanting to aim the tag with the keys is absurdly impossible as it would require both the mouse to happen to be on the same X and that the lines displaced per scroll coincides.
Alternative partial solution: at least, collapse the box after using the arrows, so it doesn't survive long enough and its annoyance is greatly reduced.
I recently discovered the https://ux.stackexchange.com/ site, and after seeing some examples of the little things that annoy users, I was couldn't be more convinced this was one of them.
